1. Field of the Invention
This invention relates to the art of abrasive devices having sharp abrasive particles anchored on a structural base, such as a metal strip. Specifically, the invention deals with metal fingernail files with aluminum oxide sharp pointed granules or grits of selected size coated on a steel strip in an epoxy resin base with one or more electroplated metal layers covering the base and forming a sheath around the metal strip firmly anchoring the particles but being sufficiently frangible over the peaks of the particles to break off during use and expose the particles.
2. Prior Art
Armored metal tools having abrasive particles anchored in metal coatings on metal bases through fusion bonds are known in the art as, for example, in the Dawson U.S. Pat. No. 3,023,490. Use of adhesives to bind refractory particles to a base metal prior to fusion bonding the particles to the base at high temperatures is disclosed, for example, in the Cole U.S. Pat. No. 2,694,647. Deposition of abrasive particles on metal bases by electrolplating the base through the pores is known, for example, in the Fahnoe et al U.S. Pat. No. 2,858,256. Simultaneous electrodeposition of a metal from a liquid electrolyte and settling of particles through the liquid onto a cathode is known from the Grazen U.S. Pat. No. 2,694,647, for example. These prior methods, however, are expensive and require high temperature fusion bonding or actual plating of the base. The electrophoretic deposition procedures require formation of porous coatings and deposition of the electrolplate through the pores onto the underlying bare metal. The present invention now utilizes a resin coating to initially deposit the abrasive particle on the metal base and then uses electroplating procedures to form a plated metal sheath or shell around the base which will firmly anchor the particles preventing them from being pulled out and yet being thin and frangible enough to break off at the discrete peaks of the particles for exposing them to the surface to be abraded.